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Comment Secure pairing is hard (Score 4, Interesting) 131

This is a general problem with devices that are "paired". How do you securely establish the initial connection, when neither side knows anything about the other?

The secure solutions involve some shared secret between the two devices. This requires a secure transmission path between the devices, such as typing in a generated key (like a WPA2 key) or physically carrying a crypto key carrier to each device (this is how serious cryptosystems work).

Semi-secure systems involve things like creating a short period of temporary vulnerability (as with Bluetooth pairing). There's a scheme for sharing between cellphones where you bump the phones together, and they both sense the deceleration at close to the same time.

Comment This is a job for QNX (Score 1) 161

Consider trying QNX, the message-passing real time OS, for this. This is a message passing problem, and Linux doesn't do message passing well. QNX has a scheduler optimized for message passing. You should be able to handle the UDP front end and fan-out without any problems. You can give the front-end process a higher priority than the other processes, which should let you get all the UDP packets into the fan-out program without losing any. That's what real-time OSs are for.

Trying to do anything high-performance with CPython's threads is hopeless. Watch this presentation on performance issues with Python's Global Interpreter Lock, Python has an internal scheduler, and it behaves very badly under load.

So each Python process should be single-thread. Have as many as you need, set up to get work via MsgReceive and reply by MsgReply. Don't set them up as "resource managers".

Python under QNX is being used by the robotics community, where real-time matters for some things, but not others.

QNX - great technology, marketing operation from hell.

Comment This belongs in the cluster manager (Score 4, Informative) 161

That level of control probably belongs at the cluster management level. We need to do less in the OS, not more. For big data centers, images are loaded into virtual machines, network switches are configured to create a software defined network, connections are made between storage servers and compute nodes, and then the job runs. None of this is managed at the single-machine OS level.

With some VM system like Xen managing the hardware on each machine, the client OS can be minimal. It doesn't need drivers, users, accounts, file systems, etc. If you're running in an Amazon AWS instance, at least 90% of Linux is just dead weight. Job management runs on some other machine that's managing the server farm.

Comment Tax advertising (Score 1) 418

There is a serious bipartisian proposal in Congress to reduce the tax deduction for advertising. Call your Congressional representative and tell them you support the elimination of tax deductions for advertising.

Because the US savings rate is so low (most people are spending almost all they earn), advertising does not increase demand. It just moves it around a bit. All advertising does is increase prices. There are many products, from movies to medications, where the advertising cost exceeds the cost of production. Let's put the brakes on advertising.

Comment Re:Derp (Score 2, Informative) 168

Surely you must be joking. There have been Explorer bugs that went unpatched for six months. No operating system is immune and security flaws arising from bugs in code are an inevitable accompaniment to having code in the first place, especially complex code with lots of moving parts (some of them infrequently tested/visited), but Microsoft has historically been Macrosquishy when it comes to security and patches. LOTS of holes, and many of them (in the historical past) have taken a truly absurd amount of time to be patched, resulting in truly monumental penetration of trojans and viruses via superrating wounds like Outlook. I still get an average of one email message a day that makes it through my filters purporting to be from a correctly named friend or a relative and encouraging me to click on a misspelled link. You think those messages are arising from successful data-scraping via Linux malware or Apple malware or FreeBSD malware?

Perhaps, driven by the need to actually compete with Apple and Linux (including Android) instead of resting on their monopolistic laurels, they have cleaned up their act somewhat over the last few releases of Windows, but on average over the last 10 or 15 years, certainly since the widespread adoption of apt and yum to auto-maintain Linux, the mean lifetime of a security hole in a Linux based system all the way out to user desktops has been around 24 hours -- a few hours to patch it and push it to the master distro servers, mirror it, and pull it with the next update. Microsoft hasn't even been able to acknowledge that a bug exists on that kind of time frame, let alone find the problem in the code, fix it, test it, and push it.

If they are doing better now, good for them! However, look at the relative penetration of malware even today. Linux malware has a very hard time getting any sort of traction. Apple malware has a very hard time getting any sort of traction. Windows? It's all too easy to whine that it gets penetrated all the time because it is so popular and ubiquitous, except that nowadays it is neither.

rgb

Comment Re:it is the wrong way... (Score 2) 291

Why would you assume he would compensate people for something that was being removed?

Maybe because before the election, Abbott promised to keep those tax cuts after repealing the carbon tax?

But you are right, I didn't assume it would stay. At time Abbott was making a whole pile of promises and he could not keep then all - balance the budget, reduce taxes, keep all the benefits those taxes paid for. But by that time hearing him make promises he could not keep was no surprise. It was clear by then the man would say anything, do anything, prostitute anything (including the sexuality of his daughter) in order to get into power.

Amazingly this extraordinary behaviour got worse after he was elected. (Amazing to me anyway. I didn't think it was possible.) First we had a promise to be an open transparent government, then a week or two later we learnt a phrase: "on water matters". Who still remembers the no surprises, no excuses government speech he gave after being elected. Probably not too many, given the shock the first last budget inflicted.

Comment Re:Dark energy is negative (Score 1) 214

Dark Matter and Dark Energy are two completely unrelated issues.

To a complete layman like me, it sounds from the ancestor you are posting under they could be very much related:

Negative mass reacts oppositely to both gravity and intertia. Oddly, that means that negative mass still falls down in a gravitational field: The gravitational force is opposite, but negative mass responds negatively to force (a=F/m, where both F and m are negative). So negative mass particles repel each other gravitationally, but are attracted to positive mass objects.

That sounds like a good candidate for explaining both. Space expands because Dark Matter repels itself, but it causes galaxy's to clump and gravitational lensing because it attracts ordinary matter. I did always wonder why, if Dark Matter interacts with everything so weakly, it didn't immediately clump into black holes. This would explain it.

Comment Track-train dynamics (Score 5, Informative) 195

That jet-powered locomotive was neverintended as a useful means of propulsion. It was just to test track-train dynamics at higher speed. Not much was done with the info, since Amtrak wasn't into high speed rail.

The next big advances in high speed rail were Japan's Tokaido line and San Francisco's BART, both around 1970. The original Tokaido trains had conventional wheel arrangements, and required a very good and very high maintenance roadbed. The SF BART system had the first trains with an active suspension, with each car body supported on a triangle of three air bags controlled by electronic controls. This allowed a higher body height at higher speed, allowing more wheel travel and a softer suspension. Also, all wheels were powered, as is normal in transit operations.

The French TGV brought both of those ideas together - high speed plus active suspension with more suspension travel, with all wheels powered. This allowed high speed trains without excessive track wear. (That's a big problem with high speed rail. A French test in 1955 reached 331 km/h, but damaged the track seriously in only one run. There were serious doubts for years whether steel wheel on steel rail could ever go that fast in routine operation.)

As with cars, there's been more than enough power to go fast for decades. Wheel and suspension issues are what limit speed.

Comment Few alternatives? (Score 1) 89

While that may seem slow, people in remote areas may have few alternatives.

Other than:

Solar power, at roughly $1/watt (and then "free" for 10-20 years), price falling on a nearly Moore's Law trajectory.
Wind power -- expensive, unreliable but simple technology and humidity isn't reliable either.
The entire panoply of standard sources -- coal, oil, gasoline, nuclear, hydroelectric, alcohol, diesel, methane... which we can deliver a variety of ways including simply delivering a small generator and fuel.

I would truly be amazed if a new, patented technology of this sort was within an order of magnitude -- or even two -- of the cost of a solar source superior in nearly every way, and there are very few places where the humidity is high, temperatures are reasonable, and the sun does not produce enough light to make this work. This is truly an edge technology unless they make it astoundingly cheap.

rgb

Comment The appcrap boom is over (Score 5, Insightful) 171

What "software renaissance"? The writer means the appcrap boom - millions of small bad programs, with a few good ones. Many, maybe most, "apps" could just as well be web pages.

The appcrap boom seems to be winding down. Developers realize that writing a quickie app has roughly the success percentage of starting a garage band. That's a good thing.

It's a great time to code, if you have a problem to solve. The tools are cheap if not free, the online resources are substantial, and there's vast amounts of cheap computing power available on every platform from wrist to data center. If you don't have a problem to solve, coding is sort of pointless.

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I tell them to turn to the study of mathematics, for it is only there that they might escape the lusts of the flesh. -- Thomas Mann, "The Magic Mountain"

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